Brakes on axes of multi-axis machines, in particular such as robots, have a response time and/or closing time between a switching of the brake and a response point in time at which the brake changes a motion state of the assigned axis and/or effects a change of the motion state. A motion state can in particular comprise a rotational speed, a change in rotational speed, a velocity or an acceleration, and/or a deceleration of the axis. A change in velocity and/or a change in rotational speed as defined by a change and/or switch of the motion state can for instance be defined by a relative change of the reference parameter rotational speed and/or velocity by more than approximately 2 percent, by more than approximately 5 percent, especially preferred by more than approximately 10 percent, and in particular by more than approximately 20 percent. In order to effect a specified acceleration and/or deceleration, the brake needs to apply a certain minimum brake force to thereby change the motion state. In particular, the brake can also brake with a (maximum) nominal brake force. Analogously, the brakes have an opening time between a switching of the brake and a response point in time, from which point forward the brake applies, or can apply, no more than only a certain maximum brake force, and in particular is fully vented and/or at least essentially applies, and/or can apply, no further brake force.
For purposes of a more compact description, such a closing and/or opening time is generally referred to herein as the response time of the brake. The response time of the brake can in particular depend on mechanical, hydraulic, pneumatic, (electro-) magnetic and/or signaling technology and/or energy-technical inertia, brake wear, and the like.
Closed brakes also exhibit a mechanical play, by which the axis can be moved by a certain force, in particular in the amount of the (maximum) nominal brake force. In particular, such a mechanical play can also depend on brake wear.
Having knowledge of a real-time response time and/or such a mechanical play can advantageously improve the operation and/or monitoring of the machine. For instance, if the real-time response time is known, the brake can be switched appropriately earlier or later, instead of having to do so on the basis of theoretical maximum and/or worst-case values for track planning purposes. In the same manner, a known real-time mechanical play can for instance be taken into account for track planning purposes by appropriately readjusting the axis.
If a known real-time response time and/or a known real-time mechanical play exceeds a specified limit value, a fault state can be identified on the machine monitored in this manner.
The task of the present invention is therefore to improve the operation and/or monitoring of a multi-axis machine, in particular a robot.